Distinguishing coherent and thermal photon noise in a circuit QED system

In the cavity-QED architecture, photon number fluctuations from residual cavity photons cause qubit dephasing due to the AC Stark effect. These unwanted photons originate from a variety of sources, such as thermal radiation, leftover measurement photons, and crosstalk. Using a capacitively-shunted flux qubit coupled to a transmission line cavity, we demonstrate a method that identifies and distinguishes coherent and thermal photons based on noise-spectral reconstruction from time-domain spin-locking relaxometry. Using these measurements, we attribute the limiting dephasing source in our system to thermal photons, rather than coherent photons. By improving the cryogenic attenuation on lines leading to the cavity, we successfully suppress residual thermal photons and achieve $T_1$-limited spin-echo decay time. The spin-locking noise spectroscopy technique can readily be applied to other qubit modalities for identifying general asymmetric non-classical noise spectra

Evolving marine biosecurity in the Galapagos Islands

Some of my co-authors and I have just returned from one of the paradises on earth and a natural history mecca – The Galapagos Islands, Ecuador. We participated in (MLC, CLH) or hosted (IK, TD, KC) the 1st Tropical Island Marine Bioinvasions Workshop convened at the Charles Darwin Research Station. From a terrestrial standpoint, the Ecuadorian government’s biosecurity for the most part is intelligent (but see Gardener et al. 2010), well organised and seems to be effective, with a number of publications detailing introduced terrestrial plant (e.g., Buddenhagen 2006; Jager and Kowarik 2010) and animal (e.g., Cruz et al. 2005; Carrion et al. 2011) eradications and impacts (e.g., Schofield 1989; Itow 2003; Renteria et al. 2012; Kueffer et al. 2010), invasion risks (e.g., Gottdenker et al. 2005), and ecosystem restoration, management and conservation (e.g., Gibbs et al. 1999; Causton et al. 2006). Yet, as with so many other systems, marine biosecurity lags behind (a quick review of the literature shows no marine introduction publications) and is consequently less well managed, but not for a lack of effort

Evolution of the E(1/21+)−E(3/21+)E(1/2^+_1)-E(3/2^+_1) energy spacing in odd-mass K, Cl and P isotopes for N=20−28N=20-28

The energy of the first excited state in the neutron-rich N=28 nucleus 45Cl has been established via in-beam gamma-ray spectroscopy following proton removal. This energy value completes the systematics of the E(1/2^+_1)-E(3/2^+_1) level spacing in odd-mass K, Cl and P isotopes for N=20-28. The results are discussed in the framework of shell-model calculations in the sd-fp model space. The contribution of the central, spin-orbit and tensor components is discussed from a calculation based on a proton single-hole spectrum from G-matrix and pi + rho meson exchange potentials. A composite model for the proton 0d_{3/2}-1s_{1/2} single-particle energy shift is presented.Comment: Phys. Rev. C, in pres

Two-neutron knockout from neutron-deficient 34^{34}Ar, 30^{30}S, and 26^{26}Si

Two-neutron knockout reactions from nuclei in the proximity of the proton dripline have been studied using intermediate-energy beams of neutron-deficient $^{34}$Ar, $^{30}$S, and $^{26}$Si. The inclusive cross sections, and also the partial cross sections for the population of individual bound final states of the $^{32}$Ar, $^{28}$S and $^{24}$Si knockout residues, have been determined using the combination of particle and $\gamma$-ray spectroscopy. Similar to the two-proton knockout mechanism on the neutron-rich side of the nuclear chart, these two-neutron removal reactions from already neutron-deficient nuclei are also shown to be consistent with a direct reaction mechanism.Comment: Phys. Rev. C, rapid communication, in pres

Ly6c+ “inflammatory monocytes” are microglial precursors recruited in a pathogenic manner in West Nile virus encephalitis

In a lethal West Nile virus (WNV) model, central nervous system infection triggered a threefold increase in CD45int/CD11b+/CD11c− microglia at days 6–7 postinfection (p.i.). Few microglia were proliferating, suggesting that the increased numbers were derived from a migratory precursor cell. Depletion of “circulating” (Gr1−(Ly6Clo)CX3CR1+) and “inflammatory” (Gr1hi/Ly6Chi/CCR2+) classical monocytes during infection abrogated the increase in microglia. C57BL/6 chimeras reconstituted with cFMS–enhanced green fluorescent protein (EGFP) bone marrow (BM) showed large numbers of peripherally derived (GFP+) microglia expressing GR1+(Ly6C+) at day 7 p.i., suggesting that the inflammatory monocyte is a microglial precursor. This was confirmed by adoptive transfer of labeled BM (Ly6Chi/CD115+) or circulating inflammatory monocytes that trafficked to the WNV-infected brain and expressed a microglial phenotype. CCL2 is a chemokine that is highly expressed during WNV infection and important in inflammatory monocyte trafficking. Neutralization of CCL2 not only reduced the number of GFP+ microglia in the brain during WNV infection but prolonged the life of infected animals. Therefore, CCL2-dependent inflammatory monocyte migration is critical for increases in microglia during WNV infection and may also play a pathogenic role during WNV encephalitis

Shell structure at N=28 near the dripline: spectroscopy of 42^{42}Si, 43^{43}P and 44^{44}S

Measurements of the N=28 isotones 42Si, 43P and 44S using one- and two-proton knockout reactions from the radioactive beam nuclei 44S and 46Ar are reported. The knockout reaction cross sections for populating 42Si and 43P and a 184 keV gamma-ray observed in 43P establish that the d_{3/2} and s_{1/2} proton orbits are nearly degenerate in these nuclei and that there is a substantial Z=14 subshell closure separating these two orbits from the d_{5/2} orbit. The increase in the inclusive two-proton knockout cross section from 42Si to 44S demonstrates the importance of the availability of valence protons for determining the cross section. New calculations of the two-proton knockout reactions that include diffractive effects are presented. In addition, it is proposed that a search for the d_{5/2} proton strength in 43P via a higher statistics one-proton knockout experiment could help determine the size of the Z=14 closure.Comment: Phys. Rev. C, in pres

Population of bound excited states in intermediate-energy fragmentation reactions

Fragmentation reactions with intermediate-energy heavy-ion beams exhibit a wide range of reaction mechanisms, ranging from direct reactions to statistical processes. We examine this transition by measuring the relative population of excited states in several sd-shell nuclei produced by fragmentation with the number of removed nucleons ranging from two to sixteen. The two-nucleon removal is consistent with a non-dissipative process whereas the removal of more than five nucleons appears to be mainly statistical.Comment: 5 pages, 6 figure

Interleukin-6 gene (IL-6): a possible role in brain morphology in the healthy adult brain

Background: Cytokines such as interleukin 6 (IL-6) have been implicated in dual functions in neuropsychiatric disorders. Little is known about the genetic predisposition to neurodegenerative and neuroproliferative properties of cytokine genes. In this study the potential dual role of several IL-6 polymorphisms in brain morphology is investigated. Methodology: In a large sample of healthy individuals (N = 303), associations between genetic variants of IL-6 (rs1800795; rs1800796, rs2069833, rs2069840) and brain volume (gray matter volume) were analyzed using voxel-based morphometry (VBM). Selection of single nucleotide polymorphisms (SNPs) followed a tagging SNP approach (e.g., Stampa algorigthm), yielding a capture 97.08% of the variation in the IL-6 gene using four tagging SNPs. Principal findings/results: In a whole-brain analysis, the polymorphism rs1800795 (−174 C/G) showed a strong main effect of genotype (43 CC vs. 150 CG vs. 100 GG; x = 24, y = −10, z = −15; F(2,286) = 8.54, puncorrected = 0.0002; pAlphaSim-corrected = 0.002; cluster size k = 577) within the right hippocampus head. Homozygous carriers of the G-allele had significantly larger hippocampus gray matter volumes compared to heterozygous subjects. None of the other investigated SNPs showed a significant association with grey matter volume in whole-brain analyses. Conclusions/significance: These findings suggest a possible neuroprotective role of the G-allele of the SNP rs1800795 on hippocampal volumes. Studies on the role of this SNP in psychiatric populations and especially in those with an affected hippocampus (e.g., by maltreatment, stress) are warranted.Bernhard T Baune, Carsten Konrad, Dominik Grotegerd, Thomas Suslow, Eva Birosova, Patricia Ohrmann, Jochen Bauer, Volker Arolt, Walter Heindel, Katharina Domschke, Sonja Schöning, Astrid V Rauch, Christina Uhlmann, Harald Kugel and Udo Dannlowsk

Barriers to obesity management: a pilot study of primary care clinicians

BACKGROUND: Obesity is an increasing epidemic in both the US and veteran populations, yet it remains largely understudied in the Veteran's Health Administration (VHA) setting. The purpose of our study was to identify barriers to the effective management of obesity in VHA primary care settings. METHODS: Three focus groups of clinicians from a Veteran's Affairs Medical Center (VAMC) and an affiliated Community Based Outpatient Center (CBOC) were conducted to identify potential barriers to obesity management. The focus groups and previously published studies then informed the creation of a 47-item survey that was then disseminated and completed by 55 primary care clinicians. RESULTS: The focus groups identified provider, system, and patient barriers to obesity care. Lack of obesity training during medical school and residency was associated with lower rates of discussing diet and exercise with obese patients (p < 0.05). Clinicians who watched their own diets vigorously were more likely to calculate BMI for obese patients than other clinicians (42% vs. 13%, p < 0.05). Many barriers identified in previous studies (e.g., attitudes toward obese patients, lack of insurance payments for obesity care) were not prevalent barriers in the current study. CONCLUSION: Many VHA clinicians do not routinely provide weight management services for obese patients. The most prevalent barriers to obesity care were poor education during medical school and residency and the lack of information provided by the VHA to both clinicians and patients about available weight management services